Jib crane

ABSTRACT

This invention relates to a jib crane characterized by the fact that the top of the jib is pivoted to the main post, which travels on a single rail and the wheels at the bottom of the jib travel on an annular flange fitted around the main post.

United States Patent Murakami [4 1 Mar. 28, 1972 [54] J IB CRANE [56]References Cited [72] Inventor: Sakae Murakami, 382-2 Matsunaga- UNITEDSTATES PATENTS machi, Fukuyama, Japan 329,219 /1885 [22] Filed: Apr. 13,1970 1,551,768 9/1925 1,064,141 6/1913 [21] Appl. No.. 27,520 3,262,4007,1966 3,391,810 7/1968 Foreign Application Priority Data PrimaryExaminer-Joseph Wegbreit FCb. 13, 1970 Japan Anomey uolcombe wetheri" &Brisebois [52] US. Cl. ..2l2/l7, 212/55 57 ABSTRACT [51] Int. Cl. B660:23/04 I 1 58 Field of Search ..212/17, 65, 69, 2s, 61, 55; Thisinvention relates to a j crane characterized y e t that the top of thejib is pivoted to the main post, which travels on a single rail and thewheels at the bottom ofthe jib travel on an annular flange fitted aroundthe main post.

2 Claims, 6 Drawing Figures PATENTEUHARZB 1972 SHEET 1 OF 3 FIG.

PATENTEDmza 1972 3,651,951

' SMEI 2 UF 3 PATENTED MR 2 8 1972 SHEET 3 BF 3 FIGS FIG.6

.Im CRANE SUMMARY OF THE INVENTION A This invention relates to a jibcrane. The object of this invention is to provide a jib crane travelingon a single rail and having a load supporting member which may be swungthrough an angle of 360.

A conventional jib crane travels on two rails and the jib is pivoted toswing freely about the main post. Since it needs two rails, itsinstallation takes up a great deal of space; it cannot swing through360; and it has a complicated mechanism.

These disadvantages are overcome by my invention, a preferred embodimentof which is illustrated in the accompanying drawings, in which:

FIG. 1 is a side view of a jib crane according to my invention;

FIG. 2 is a sectional view taken along the line II-Il of FIG. 1;

FIG. 3 is a partial longitudinal sectional view of the swingable part ofthe jib;

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is a side view of the traveling part; and

FIG. 6 is a sectional view of the hoist supporting beam.

Referring now to FIG. 1, it will be seen that my crane comprises asingle supporting rail 1 and a single guide rail 2 parallel to and abovethis rail. In the drawing, this guide rail is shown with a C-shapedsection.

As seen on FIGS. 1 and 5, a base frame 3 equipped with wheels 4, whichroll on the rail 1, and with two rollers 6 which contact both sides ofthe vertical web of this traveling rail 1 is mounted upon the supportingrail 1. The rollers 6 have a narrow stepped upper portion 6', best seenin FIG. 5. The lateral edges of the upper part of the rail are grippedbetween the stepped portions 6 and the lower surfaces of this upper partengage the wider portions of the rollers. The wheels 4 of the base frame3 roll on the rail 1 and are driven by a motor 5 on the frame 3.

The main post 7 stands upright on the base frame 3. From the top end ofthe main post 7 projects a pin 8, at the top of which is rotatablymounted a roller 9, which engages the groove in the above-mentionedguide rail 2.

As seen in FIGS. 3 and 4, the main post 7 carries an annular flange 10.The upper end of the base of the jib 12 is pivotally mounted by means ofthe bearing 11 on the pin 8 at the top of the main post. The wheels 13attached to the lower part of the base of the jib 12 contact the annularflange of the main post. These wheels are mounted on the same shaft asthe large gear 15 driven by the motor 14. Therefore, when the motor 14runs, its motion is transmitted to the wheels, which, guided by theannular flange 10, travel, together with the jib 12, around the mainpost. The arrangement is more stable, when there are two wheels whichcontact the annular flange 10. In FIG. 3, 16 is a plate which servesboth as the stand for the motor 14 and as a bearing and this plate isfixed to the jib 12. An adequate number of rollers 17 (FIG. 6) arelongitudinally spaced along the jib l2 and arranged oppositely in tworows. These rollers 17 engage guide frames 19 having an approximatelyC-shaped section which are welded to the low sides of the main beam 18which guides the hoist. Further, pulleys 20, 21 are attached to the tipand base of the jib l2 and between these pulleys is stretched an endlesswire rope 22 or the like, one part of which is attached at 23to the mainbeam 18. When these pulleys 20, 21 are properly rotated, the main beam18 is moved toward or away from the main post 7. The hoist 24 isattached to the main beam 18 and can travel freely on the beam 18.

Such being the composition of the jib crane of this invention, the jibcrane can travel on the rail through an angle of 360 to lift or move adesired load easily.

As the jib crane of this invention needs only a single traveling rail,it takes less space for installation than a conventional one which needstwo rails. Moreover, since the wheels 4 of the base frame of the mainpost contact the u per surface of the rail 1 and the rollers 6, contactthe undersl e of the upper part of the'rail 1 and its vertical web, thecrane is not likely to get derailed, regardless of the direction fromwhich the load is applied to the crane. Since the base of the jibrotatably supports the upper part, and the lower part, being supportedby rollers, can turn along the annular flange of the main post as aguide, the jib can swing very smoothly up to 360.

What is claimed is:

1. A jib crane comprising:

a single supporting rail comprising a vertical web and a transverseupper part wider than said web;

a guide rail parallel to and above said supporting rail;

a base frame supported by wheels which roll on said supporting rail andcarrying two rollers which grip opposite sides of said supporting rail,said rollers being stepped to simultaneously contact both said web andthe lower surface of said transverse part;

a main post which stands upright on said base frame, and

has an upper end engaging said guiderail;

a transverse annular flange carried by said post; and

a jib having vertically spaced parts pivoted to said main post, carryinga motor and wheels driven by said motor which travel on said annularflange.

2. A jib crane as claimed in claim 1 in which said jib comprises a boxframe, and an l-beam suspended from said boxframe and longitudinallyslidable relative to said box-frame, said beam carrying a hoistsuspended from rollers and mounted to travel along said beam.

1. A jib crane comprising: a single supporting rail comprising avertical web and a transverse upper part wider than said web; a guiderail parallel to and above said supporting rail; a base frame supportedby wheels which roll on said supporting rail and carrying two rollerswhich grip opposite sides of said supporting rail, said rollers beingstepped to simultaneously contact both said web and the lower surface ofsaid transverse part; a main post which stands upright on said baseframe, and has an upper end engaging said guide rail; a transverseannular flange carried by said post; and a jib having vertically spacedparts pivoted to said main post, carrying a motor and wheels driven bysaid motor which travel on said annular flange.
 2. A jib crane asclaimed in claim 1 in which said jib comprises a box frame, and anI-beam suspended from said box-frame and longitudinally slidablerelative to said box-frame, said beam carrying a hoist suspended fromrollers and mounted to travel along said beam.